| In the light of the serious thick rotten disease of Z. jujube cv. Jinsixiaozao in the Jinsixiaozao production areas of Hebei province, Shandong province and Tianjin, by the studies of many years in laboratory and field, this report has defmited a few issues as follows.1 The harm, symptoms and pathogen of the thick rotten disease of Z. jujube cv. JinsixiaozaoThe investigation on thick rotten disease of Z. jujube cv. Jinsixiaozao during 1998-2000 indicated that this disease generally occurred in the Jinsixiaozao production areas in Hebei province (Cangzhou city and Langfang city), Shandong province (Laoling, Wudi and Qingyun) and Tianjin (Jinghai and Beichen). It was most serious in Botou county, Hebei province, with a 36.7% of disease rate and 26.9 of disease index in the 3 years, while the highest incidence and disease index reached 36.7% and 26.9 respectively.Three pathogens of this disease were isolated with Koch's postulates and identified as Physalospora obtuse, Phoma destructiva and Altemaria alternata. These 3 pathogens could infect the fruits of Jinsixiaozao singly or jointly. The isolating rate of P. obtuse was the highest and its pathogenicily was the strongest among these 3 pathogens. P. obtuse was the major pathogen of this disease.The symptoms of thick-rotten disease of Jinsixiaozao on fruits were divided into 3 types: thick-rot fruit, dark-furuncle fruit and brown-peel fruit. Different pathogen expressed different symptom. P. obtuse was the major pathogen with 94.6% of isolating rate in the thick-rot fruit. The thick-rot fruit covered 85.3% of all diseased fruits collected from field and was the major symptom of thick-rotten disease of Jinsixiaozao. P. destructiva was the major pathogen of Dark-furuncle fruit with 75.7% of isolating rate from symptomed fruits, and this symptom covered 8.6% of all diseased fruits collected from field. Two pathogens, P. destructiva and A. alternata, wereisolated from the brown-peel fruit and their isolating rates were 33.2% and 25.5% respectively, while the complex rate of the 2 pathogens was 19.1%. Brown-peel fruit covered 4.3% of all diseased fruits collected from field.2 The biologic characters of the thick rotten disease of Z, jujube cv. JinsmaozaoResults on the growth and producing conidia of these pathogens showed that different temperature, pH, light, carbon and nitrogen expressed different effects. Light has no effects on growth of P. obtuse and P. destructive! and was important to growth of A. alternate, while it was important to producing conidia of all pathogens. Light expressed different effects on their producing conidia. The optimum factors for growth and producing conidia of these pathogens were determined. Growth of P. obtuse: 30, pH 5 or pH 9, soluble starch, ammonium sulfate and peptone. Producing conidia of P. obtuse: 20, pH 9, light, sucrose and potassium nitrate. Growth of P. destructive. 30, pH 7, maltose, sucrose, fructose, soluble starch, ammonium sulfate, and peptone or urea. Producing conidia of P. destructiva: 25, pH 7, dark, soluble starch and potassium nitrate. Growth of A. alternata: 30, pH 9, light, maltose, sucrose, lactose and ammonium potassium nitrate or urea. Producing conidia of A. alternata: 10, pH 9, light/dark, sucrose and potassium nitrate.The interstitial fluid of the fruits significantly stimulated germination of conidia. The germination rates for P. obtuse, P. destructiva, and A. alternata reached 98.3%. 85.6% and 91.5% in 24h.Result from the antagonism test for these pathogens showed that there was no antagonism among them.3 The regularity of development of the thick rotten disease of Z. jujube cv. JinsixiaozaoThe three pathogens could over winter in jujube and diseased residuals, and the poplars, elm, peach, apple and pear around jujube orchard. These overwintering hosts became the primary infection source for this disease. Pathogens started to infest the organs of jujube in late April. Flowers infected in late May, fruit stalks in middle June, fruits in late June and early July, and the i...
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